Fix ImportErrors on Multinode if package not present (#15963)

(cherry picked from commit cbd4dd6)
Lightning-AI · Dec 8, 2022 · f130c54 · f130c54
1 parent 7deac02
commit f130c54
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Showing 3 changed files with 17 additions and 10 deletions.
diff --git a/src/lightning_app/CHANGELOG.md b/src/lightning_app/CHANGELOG.md
@@ -48,6 +48,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed PythonServer generating noise on M1 ([#15949](https://github.com/Lightning-AI/lightning/pull/15949))
 - Fixed multiprocessing breakpoint ([#15950](https://github.com/Lightning-AI/lightning/pull/15950))
 - Fixed detection of a Lightning App running in debug mode ([#15951](https://github.com/Lightning-AI/lightning/pull/15951))
+- Fixed `ImportError` on Multinode if package not present ([#15963](https://github.com/Lightning-AI/lightning/pull/15963))
 
 ## [1.8.3] - 2022-11-22
 

diff --git a/src/lightning_app/components/multi_node/lite.py b/src/lightning_app/components/multi_node/lite.py
@@ -37,11 +37,14 @@ def run(
         mps_accelerators = []
 
         for pkg_name in ("lightning.lite", "lightning_" + "lite"):
-            pkg = importlib.import_module(pkg_name)
-            lites.append(pkg.LightningLite)
-            strategies.append(pkg.strategies.DDPSpawnShardedStrategy)
-            strategies.append(pkg.strategies.DDPSpawnStrategy)
-            mps_accelerators.append(pkg.accelerators.MPSAccelerator)
+            try:
+                pkg = importlib.import_module(pkg_name)
+                lites.append(pkg.LightningLite)
+                strategies.append(pkg.strategies.DDPSpawnShardedStrategy)
+                strategies.append(pkg.strategies.DDPSpawnStrategy)
+                mps_accelerators.append(pkg.accelerators.MPSAccelerator)
+            except (ImportError, ModuleNotFoundError):
+                continue
 
         # Used to configure PyTorch progress group
         os.environ["MASTER_ADDR"] = main_address

diff --git a/src/lightning_app/components/multi_node/trainer.py b/src/lightning_app/components/multi_node/trainer.py
@@ -37,11 +37,14 @@ def run(
         mps_accelerators = []
 
         for pkg_name in ("lightning.pytorch", "pytorch_" + "lightning"):
-            pkg = importlib.import_module(pkg_name)
-            trainers.append(pkg.Trainer)
-            strategies.append(pkg.strategies.DDPSpawnShardedStrategy)
-            strategies.append(pkg.strategies.DDPSpawnStrategy)
-            mps_accelerators.append(pkg.accelerators.MPSAccelerator)
+            try:
+                pkg = importlib.import_module(pkg_name)
+                trainers.append(pkg.Trainer)
+                strategies.append(pkg.strategies.DDPSpawnShardedStrategy)
+                strategies.append(pkg.strategies.DDPSpawnStrategy)
+                mps_accelerators.append(pkg.accelerators.MPSAccelerator)
+            except (ImportError, ModuleNotFoundError):
+                continue
 
         # Used to configure PyTorch progress group
         os.environ["MASTER_ADDR"] = main_address